The rapid development of the mobile internet and the internet of things trigger explosive increase of data traffic and extensive appearance of diversified and differentiated services. The fifth generation mobile communication technology (5G), serving as a new generation mobile communication technology, will support a higher rate, a huge number of links, an ultralow delay, higher reliability, hundredfold increase of energy efficiency and the like so as to support requirement changes. The ultralow delay, serving as a key index of the 5G technology, directly affects development of delay-limited services such as car networking, industrial automation, remote control and smart grids. A current series of standard researches on 5G delay reduction is promoting gradually.
The reduction of a Transmission Time Interval (TTI), serving as an important research direction of delay reduction, aims to reduce the length of a current TTI of 1 ms to 0.5 ms or even 1 to 2 symbols, thereby shortening minimum scheduling time exponentially. Thus, a single transmission delay can be reduced exponentially without changing the frame structure.
However, when the length of the TTI is reduced to a length of 1 to 7 symbols, the transmission structure of a related Physical Uplink Control Channel (PUCCH) for sending an Acknowledgement (ACK) and a Negative Acknowledgement (NACK) cannot be directly used. Meanwhile, shortening of the TTI in time domain will affect the demodulation performance of transmitted information, and the related PUCCH is in shortage of frequency domain diversity due to occupancy of only one Physical Resource Block (PRB) in frequency domain. In addition, reduction of the number of symbols within the TTI will cause reduction of available resources for transmitting valid data due to excessive overheads of a Reference Symbol (RS).